solar wind

2022 Space Weather Summer School

whawkins — Tue, 30 Aug 2022 15:45:48 +0000

2022 Space Weather Summer School whawkins Tue, 08/30/2022 - 09:45

Author:

whawkins

Aug 30, 2022

FYI, we will not be holding a Space Weather Summer School in 2023. We hope to resume in 2024.

HAO held the latest in a series of successful Space Weather Summer Schools in Boulder, Colorado during the last 2 weeks of July. This unique educational workshop brought together 31 students mainly from the United States along with two students from abroad. Lecturers included experts in solar physics, solar wind, magnetsophere, and ionosphere-thermosphere in order to provide the students with a comprehensive background of the complete space weather system. In addition to lectures on the physics of the system, students learned from experts at the Space Weather Prediction Center about the challenges in making accurate space weather forecasts. Specialists provided an understanding of how space weather processes turn into impacts in human systems such as the power grid. Each day of the school included a computer-based laboratory exercise that let the students get hands-on experience with the models used to simulate space weather. HAO was pleased to once again provide students with an informative, comprehensive, and well well-appreciated introduction to space weather.

SWSS 2022 Group Photograph

Space Storms in the Upper Atmosphere and Ionosphere

kolinski — Mon, 22 Nov 2021 18:42:26 +0000

Space Storms in the Upper Atmosphere and Ionosphere kolinski Mon, 11/22/2021 - 11:42

Detecting the Chromospheric Footpoints of the Solar Wind

kolinski — Tue, 16 Nov 2021 21:53:48 +0000

Detecting the Chromospheric Footpoints of the Solar Wind kolinski Tue, 11/16/2021 - 14:53

Publication: ApJL; Authors: Paul Bryans, Scott McIntosh, David Brooks, Bart De Pontieu

Author:

kolinski

Nov 16, 2021

Coronal Holes present the source of the fast solar wind. However, the fast solar wind is not unimodal—there are discrete, but subtle, compositional, velocity, and density structures that differentiate different coronal holes as well as wind streams that originate within one coronal hole. In this Letter we exploit full-disk observational “mosaics” performed by the Interface Region Imaging Spectrograph (IRIS) spacecraft to demonstrate that significant spectral contrast exists within the chromospheric plasma of coronal holes.

SDO and IRIS full-disk observations from 2016 Feb 22. The HMI and AIA Frankenmaps (panels A and B) are constructed of sub-images with the same fields of view and timing of the IRIS rasters that comprise the mosaic. The CHs in the northern hemisphere and at the south pole are most evident in the AIA intensity image (B), but not in Mg II intensity (C). The CHs are evident, however, in the Mg II peak separation map (D). After removing the center-to-limb variation, this is even clearer (F).

The spectral contrast seen delineates topological differences within the globally open structure. In particular, we show that the “peak separation” of the Mg II h line at 2803 A illustrates changes in what appear to be open magnetic features within a coronal hole. These observations point to a chromospheric source for the inhomogeneities found in the fast solar wind. These chromospheric signatures can provide additional constraints on magnetic field extrapolations close to the source, potentially on spatial scales smaller than from traditional coronal hole detection methods based on intensity thresholding in the corona. This is of increased importance with the advent of Parker Solar Probe and Solar Orbiter and the ability to accurately establish the connectivity between their in situ measurements and remote sensing observations of the solar atmosphere.

Geospace response to an extreme solar flare

kolinski — Mon, 15 Nov 2021 21:58:00 +0000

Geospace response to an extreme solar flare kolinski Mon, 11/15/2021 - 14:58

Publication Name: AGU Advances; HAO Author: Jing Liu; Authors names as listed: Jing Liu, Wenbin Wang, Liying Qian, William Lotko, Alan G. Burns, Kevin Pham, Gang Lu, Stanley C. Solomon, et al.

Author:

kolinski

Nov 15, 2021

Solar flares—a sudden eruption of electromagnetic radiation at the Sun—are known to have significant impacts on Earth’s upper atmosphere and ionosphere, but their collective effects on geospace as an integrated system have never been examined. We use a newly developed whole geospace model, combined with key observational data, to study the effects of the 6 September 2017 X9.3 flare on the geospace system.

Solar flare effects on magnetospheric convection and ionospheric potential. Comparison of 50-minute averages (12:02-12:51 UT) from LTR simulations of magnetospheric and ionospheric states on September 6, 2017 with and without solar flare effects. Bottom row: LTR-simulated magnetospheric convection velocity in equatorial plane (ZGSM = 0) with (A) and without (B) solar flare effects and their difference (C). Arrows indicate direction and magnitude (also in color) of the convection velocity projected onto the plane. Top row: High-latitude electric potential, essentially convection streamlines in the ionosphere with (D) and without (E) solar flare effects and their difference (F). The minimum and maximum potentials are labeled below panels (D-F).

The analysis shows that the solar wind-magnetosphere interaction, magnetotail, field-aligned current distribution, auroral precipitation and high-latitude ionospheric convection respond to atmospheric absorption of solar flare radiation. This study, for the first time, demonstrates that a rapid and large increase in the iono-spheric E-region photoionization due to a solar transient event globally modifies the electrodynamic cou-pling of the geospace system.

solar wind

2022 Space Weather Summer School

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Space Storms in the Upper Atmosphere and Ionosphere

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Detecting the Chromospheric Footpoints of the Solar Wind

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Geospace response to an extreme solar flare

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